This invention is directed at the production of foam for the purpose of fire prevention and suppression. More particularly it is directed at the method and apparatus for making compressed air foam to be used in stationary or portable fire fighting systems and emergency response units. The system is particularly applicable to portable systems used in forestry, structure protection, rural and urban grass fires (Class A fires), and oil and gas fires (Class B fires).
For some time foaming agents have been used to increase the effectiveness of water in the prevention and suppression of fires. Systems have traditionally used foaming .agents, commonly known as surfactants, mixed in holding tanks or introduced into the water stream by a variety of methods. More recently systems have been developed which also provide for the injection of compressed air into the water/surfactant mixture to provide an improved quality and volume of foam.
Some apparatus for metering the surfactant into the water and injecting the air into the said mixture have been developed but these systems have been large, complex, difficult to operate and in general did not give adequate control over water, surfactant, and air volumes.
The weight and size of the apparatus and the operational difficulties associated with them have caused the technology to be ignored in many instances where the use of Compressed Air Foam (CAF) could be very beneficial in the prevention and suppression of fires.
The apparatus have in general been too heavy and too difficult to operate for forestry applications as the equipment must be transported into remote areas, often by helicopter, and are operated by relatively untrained personnel. Although senior forestry officials have understood the benefits of CAF systems for some time, implementation of the technology has been very slow because of these problems.
Rural fire departments have had problems for many years with the distances they must travel to reach fires. This problem is becoming worse as rural populations decrease and pressure on financial resources increase. There has been some recognition that CAF systems could be beneficial in addressing these problems as they provide a method of utilizing smaller and more economical equipment which could be spread more evenly over the area. As in the forestry sector, however, the CAF systems were too big, too expensive, and too difficult to operate for widespread use.
With the rural depopulation referred to above farms have become larger and more capital intensive. With investments in buildings and equipment often reaching into the millions of dollars, depending on volunteer fire departments located many miles away no longer makes economic sense. Also, because of the scarcity of water in many locations a fire truck maintained on site is often not effective. CAF systems address the issue of water shortage as they extend the fire fighting capabilities of water by from six to twenty times. As with the previous market areas existing CAF systems were too expensive, to complicated, and too large for widespread use.
Many resorts are located in remote locations have similar fire protection problems to large farms. In addition they must often contend with forest fires. Although these resorts usually do not have the resources to maintain their own full scale fire departments, they must upgrade their fire fighting capabilities. Again, CAF units offer the capabilities required provided the aforementioned problem areas are resolved.